Gabeiel van oobdt



UNI ED STATES PATENT cur os.

GABRIEL VAN. oomrr, or BASEL, SWITZERLAND, assrsnon T socm'rn mourns nnsusnvns GIULINI, or BASEL, swrrznnnnnn.

rnocnss 1m mcnnasmo THE nnmmnssann TEN-ACITY or METALS AND THE EASE a orTHEIR wonxms wrrncur'rme-roonsi a p. 1,326,77 Specification of LettersPatent. Pate ted D 1919. no Drawing. Application filed April 30, 1919.,Serial m. 293,883. To all whom it may concern: a a low or ahightemperature'and b d- Be it known that I, GABRIEL VAN OORDT, uallyraising or lowering the temperature Phil. Dr., a subject or the Queen.of the can ascertain that at which hardness is most- Netherlands, andresident of Basel, Switzerrapidly a'cquired. If the hardening experi- '5land, have invented a new and useful Process ,ments for finding out themost advantageous for Increasing the Hardness and Tenacity hardeningtemperature of a metal are ex- -of Metals and the Easeof Their 'Workingtended over a sufficiently long time, that i o with Cutting-Tools, ofwhich the following say, over about several weeks, the results obis afull, clear, and exact specification. tained will show which is thehighest hard- 10 It is-known that the properties of metals nessobtainable for the metal in question. which are technically importantcan be in-. =By varying the temperatures, there is then fi-uencedprofoundly by heating the metal to determined the temperature at whichthis a high temperature. maximum hardness is the most quickly at- Theprinciple underlying the present intained. This temperature is thatwhich is 15 vention differs from that underlying the termed thecharacteristic heat hardening known processes for increasing thehardness temperature. 7 r and tenacity of metals and the ease of theirThe object of the invention may, however,

working with cutting toolsthat by the inalso be attained by heating themetal at a vention metals and alloys, particularly temperature below thecharacteristic heat 20 aluminium and aluminium alloys are heated,hardeniug temperature until the desired not to high temperatures, but torelatively hardness has been attained. If the temperalow temperatures,which are below the charture used is not fanbelow the characteristica'cteristic annealing temperatures of the heat hardening temperature, itis generally metal in question 3 that is to say the possible by longerheating to obtain the i '25 temperatures used for the annealing by heatmaximum hardness of the metal in question. treatment. The temperature tobe usedat ,At still lower temperatures, however, this whicha hardnessand a tenacity as great as maximum hardness is no longer obtainablepossible are obtained in the shortest time is but only a hardnesssmaller than the said another for each metal or alloy, but'an en-;maximum hardness. The hardnesses attain- 30 tirely determined one. Thistemperature able are to a certain extent proportional to may be calledthe characteristic heat hardenthe decrease of the hardeningtemperatures. ing temperature and is ascertained experi- By amodification of the invention, therementally. a fore, there is producedonly a partial harden- By the inve tion metals which are worked ing;This is sufiicient when,.for example, the i with difficulty on the latheare converted in main object is to obtain a satisfactoryv metal .a shorttime'into metals which' can be satisfor turning or similar working andnot a factorily turned and have high tenacity and metal having the.maximum hardness and hardness. By heating to a relatively low tenacity.In such a case the metal part to be temperature there is obtained inthemetal, hardened may, immediately after casting or 40 in a very shorttime, a stable structural reheating in a liquid bath, be brought into a2 equilibrium for'the' limits of the usual temsoaking pit or soakingbox, which by the peratures at which the metal is used. heat containedin the metal part is brought y The temperature of the heating is. ascer--to.'a certain temperature below the charactained experimentally bysubjecting the teristic heat hardening temperature; in this 45 metal fora period of several days toa conpit or box the metal part is left toacquire V stant temperature and then making hardness the desiredhardening. The advantage 0 tests at room temperature which clearly thisform of the invention is that fuel which show; whether hardening orsoftening has must be used for the complete heat hardenoccurred.Accordingt the indication thus ing, can be economized. At the low tem-60 obtained a further experiment at another, peratures used it may notbe necessary to higher, temperature is undertaken and anprotect themetal during heat treatment 7 other hardness test made. By thesystematic from atmospheric air by using an indifferent 106 choice oftemperatures, one can start from atmosphere or a packing.

. carried complet possible soft Y wheels, in

coolin the ot he teeth, will be er modification of the invention may beinterrupted ing for the interpo sition-of a Working operation may beseveral times repeated and the heating ely or' in part to a finish. orexample a screw thread may be cut on he preliminarily hardened metalwhen the ard sufiicient ening by strongly heating the worked surface maybe recti subsequent finishing hardening.

partial hardening of metalstance the hardening of the teet ly performedmg the p tion, such to the characteristic h arts, for inof toothed bybring hardening temperature, but bel g when operating on sma her parts.The'parts close'to thoseto rdened will then have the low tem erature atwhich in'the, same period thehlgher or maximum hardness is not attained,so that the hardened parts, for instance the the rest.

harder than 1e metals to employ for toothed Wheels ,theselatter and tothe tenacity necessary for p wheel towa to cool slowly. i Y;

11g examples illustrate'jthe inardening of the n for instance beardening temperatura' e through the middle part of. th rd the whe 11every case, rom the heat hardening tem perature to the ure has The tonevention: 7

Example'l: nsisting of 8 c the maximum Brinell 2.6, the piece while itis stll warm, after having healed at 530 to 550 C. if it was previouslysub ected to a mechamcalworkin g in a cold.

condition, is left for four to five days at a his manner the y a Brinellhard ng of the metalbeen cast or anhe small wear of e toothed el shaft,which morej treatment at cent.

The characteristic ature of 70 C. of th exa c all mple was determinemanner I the Testrace he.

its maximum is to say ness.

If after casting a mechanical wor or 530. the

Bri

worded the its call perature,; producing thus a gof-h such This tabularalloy of ,85

hardening th tility andcould umln'ium and 15 cool according of 10 mm. ofkg. show e'ss of 50 d ach of the four foll . Brinell hard ness (PTemperure.

per cent. of cent; of

days. i s to 92 per cent. 0

ammering, to 550 foll owed by air had to take hardening ness. of 50efore its nell hard turning rah e all ease y by rolling,

ardness an with cuttl a mechanical work e varia zinc attains hardness bythe allo king, as rol an annealin ng tools; I

diameter ed for th egrees Brinell. cooling.

subjected temperatures,' as for inat 40 C B it exhibit show 0y .hadfurther be dness amounts to 80-90 per ay. The

heat hardening temperoy employed in this (I in the following withcutting tools. eningto 92.6-B

piece and plece N0. 4

pieces cooled to room ected in every case to tions of'the hard piecesare shown in owing tabular exhibit: f w

150 kg. and 'D=10 mm.) er- I 5 clearly that an uminium and 15. the mosttreating i e increase .650=42.6

y wa

g of the metal at cool place befo and a test 80 e alloy the .measuredFour pieces of to heat treat- No.2 at

ents were interrupted frequi t at 70 of hard Brinell that s subjected toing, drawing.

1I1g'.dOWI1 in re its heat he alloy showing a ould diflicultly be Afterits hardrmell it could asily as I not lost its ducf be turnedon l brass.'After is necessarythat s after the heat 11.01 the in tial hardhardeningbe efiected at a temperature 'below 70 C. that is to say below. thecharacter- .istic heat hardening temperature and itis thereforeconvenient to cool'the metal fre- 6 quently during the mechanicalworking.

Example 2: Brinell hardness of 55.3 a piece of alloy c011 sisting of 98per cent. aluminium an 2 per cent. copper, While it is still warm aftercast vingor annealing, about 160 (3.,

air as described in Example 1.

in air or with exclusion of By this treatment the hardness of this alloyis in creased by about 70 per cent., hardness having been 32.7 degreesThe following tabular exhibit shows how the characteristic ture wasdetermined: v

the initial alteratiii'e.

hardness of 39.0 is attained, which is an, in-;

crease of hardness of about 10 per cent. of

' that of the unhardened zinc.

Example 4:: Pure copper having aBrinell hardness of 30 acquires peratureof about 200 (3., the increase 0 hardness being about 40 percent.

-heat'hardening temperature of 200 C. ref

u "suited 'from theex eriments shown in, the

following tabular ex ibitz; 1

-. 'lest-piec'e Tempcr- Y No. ature.

hams days. ays. days. days. days.

In 5 days the Brinellhard Example 5 ness of bronze of-Lthe composition.94 per cent. tin 15 increased cent. copper and 6 per For attaining thehighest is warmed for 10 days to I Brinell.

heat hardening tempera Templar;

and its alloys, with (1, this temperai the highest Brinell hardness of42.9 in 20 days at a tern f 25 -days produced themaximu'm Brinellhardness of 55.3 degrees. (Tliecharacteristicheat The determination of Ythe. characteristic 7 "Example 10: Pure zinc atv about 200 C. yieldedthe maximum Brinell hardness of 1 0 per cent. The like heat treatmentfor I I Bflmll hardness-(P lm kg. and D=10 I '2 mmdaiw mess of 0 percent. or 37.8 Brinell hardness.

'300 0;). Example 12: Heating at 260 C. for 10 to 65.5 by heating at atemperature of 500 C.

The increase oihardness is about 12 per cent.

Example 6: Heating brass of the composition 72 per cent. copper and 28percent.

zinc at about 300 C. for 8 days, increases the Brinellhardness to 47.4,that is'to say about 15 per cent.

' Example 7: A soft iron haying a Brine-ll hardness 85.7 hasthishardness increased to 104 by a heating for about 50 days at 300 C. Theheating should be conducted in an indifferent atmosphere or in a packingor in some other manner excluding air. The increase of hardness amountsto 21 'per cent.

After 10.days the hardness was 92.6 and after l5'days The followingtabular exhibit shows how 1 the]. characteristic heat ture of 300 C.has'been determined: Banal hardnegm(-150 kg. new

100 on the same scale.

hardening tempera- Erin ell hardness (13 150 lrgfand D=1O mm.)

y .aftere Example 8: Metal parts consisting of per cent. aluminium and15 percent. zinc were warmed at about 40 C. for 4 days and therebyattained Brinell hardness of 7 4.11 corresponding with. an increase ofhardness of 56 per, cent. '10 days heating at the same temperatureraised the hardness to 8 5.7 Brinell, an increase of 80 per cent, andthis was the maximum result of this particular heat. hardening (thecharacteristic heat hardening temperature isabout 70 (1.).

- Example-9: A piece of metal consisting per cent. aluminium and 2 percent. copper attainsa Brinell hardness of 42.9 when heated for. 10 daysat about 120 C. corresponding with an increase of hardness of about 28per cent. The like treatment for hardening temperature is about 160 C.)

heated for 2 days of 39, an increase of hardness 20 hours only producedan increase of hard- (The characteristic heat hardeningtempera- G. abrass consisting to a Brinell hardthe increase of hardness about 5 percent. (The characteristic' heat hardening temperature is about daysincreases the hardness of soft iron by tools, consisting in heating themetal'to its about per cent. (The characteristic heat characteristicheat hardening temperature or hardening temperature is about 300 0.). toa temperature below this characteristic The heat hardening treatment maybe apheat hardening temperature until the desired 5 plied to thefinished product or maybe 1nhardness has been attained. 4

,terposed intelligently between the stages of 4. The herein describedprocess for in working of the process to Which the metal is creasing thehardness, and tenacity of metals subjected. The heat hardening however,and the ease of their working w th cutting cannot be followed by anymechanical worktools, consisting in heating the metal to its 19 ing bymeans of presses, rollers, hammers or characteristic heat hardeningtemperature or the like at temperatures higher than the to a temperaturebelow this characteristic characteristic heat hardening temperature;heat hardening temperature, interrupting 0n the other hand permissiblecold working the heat hardening before the attainment of by means ofpresses, rollers, hammers, drawthe final condition, then working themetal is ings etc. produces a further increase of hardwith a cuttingtool and then continuing the ness, tenacity and ease of Working withcutheat hardening until the desired ormaxiting tool. mum hardness hasbeen attained. I V

What I claim is: 5. The herein described process for in- 1. The hereindescribed process for increasingthe hardness, and tenacity ofmetalv 2ccreasing the hardness, and tenacity'of metals articles and the ease oftheir Working with and the ease of their working with cutting cuttingtools, consisting in' heating certain tools, consisting in heating themetal to a parts of the article to the characteristic heat relativelylow temperature which is below hardening temperature or a temperaturethecharacteristic temperature for the annear the said heat hardeningtemperature,

25 nealing of the metal in question. but below it, while the other partsof the ar- 2. The herein described process for in- .ticle are kept at alower temperature, until creasing the hardness of aluminium and theparts to be hardened have attained. the aluminium alloys having apreponderating maximum or desired hardness. aluminium content, whichconsists in heat- 7 In Witness WhereofIhave hereunto signed y 30 ing themetal or alloy at-a temperature bemy name this 14th-day of April, 1919,in the tween and 200 C. until maximum hardpresence of two subscribingWitnesses. ness is attained. DR. GABRIEL VAN OORDT.

3. The herein described process for in Witnesses creasingthe hardness,and tenacity of metals 3 SOo'rr TAGGART, 35 and the ease of theirWorking with cutting I Armani) BRAM.

